1. Field of the Invention
This invention relates to devices and techniques for launching projectiles and more particularly relates to the launching of granular substances from an air-powered gun.
2. Description of the Related Art
Myriad devices and techniques are known for the launching of projectiles and have a long and well-known history. The advancement and modification of projectile launchers continues unabated. Common motivations for the use of projectile launchers include protection, elimination of pests, hunting, and recreation. The development of projectile launching devices spans the entirety of recorded history and includes recognizable examples like spear-throwers, slings, bows, ballistae, catapults, trebuchets, and a plethora of gun powder devices. One unique class of projectile launching device may be classified as an ‘air gun’. Air guns, or air-powered launching devices, were first likely developed in the late years B.C. and included the simple, yet effective blow gun. The blow gun uses human lung power to generate the pressure necessary to launch a projectile, such as a dart. One famous example of the pervasiveness of air gun utility throughout history is the pump action air rifle used by the Lewis and Clark expedition of the early 19th century.
Air guns of all types utilize the accumulated energy of compressed air as the impetus for accelerating a projectile. Quickly releasing the compressed air behind a projectile creates a difference in air pressure between the compressed air on one side of the projectile and the ambient air pressure on another side of the projectile, causing the projectile to move in the direction of lowest pressure, launching the projectile. The greater the difference between the compressed air pressure and the ambient air pressure, the more kinetic energy is transferred to the projectile.
Development in air gun technology may be considered to encompass three principal challenges. Firstly, there are challenges pertaining to the creation of air pressures higher than those provided by lung power. Increases in generated air pressure come initially with the incorporation of air bladders (similar to forge bellows), then pump action pressure accumulators, and recently prepackaged containers of pressurized gas. One source of prepackaged pressurized gas is the carbon dioxide (CO2) cartridge common to many types of air-powered devices. In one instance, the cartridge may be clipped into the butt of an air gun where an actuator draws off pressure from the cartridge to propel a projectile. In another instance, a separate auxiliary tank of CO2 is used to charge a cylinder coupled to the air-powered device.
Secondly, there are challenges relating to the production techniques and materials used for the manufacture of air guns. Superior manufacturing techniques facilitate precise tolerances among air gun components, allowing for greater projectile launching accuracy. Material components produced from metallic and polymer components, coupled with advancements in valve technology, permit greater pressures to be contained and precisely released, facilitating more power and accuracy. Thirdly, there are challenges of projectile design encompassing accuracy, quality, and function. Some examples of projectiles presently manufactured for use in air-powered guns include pellets, BBs, darts, and paintballs.
The progression of air gun development from handmade tubes using lung power to precisely manufactured implements utilizing state of the art projectiles is testament to the continuing resiliency and expanding applicability of the air gun concept. And though many advancements in the field of air gun technology have improved and/or expanded the air gun's function, most have come with a corresponding cost of ownership: chiefly the expense incurred by expending projectiles.